GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 1998 🢒 Prizm 🢒 HVAC 🢒 Heating, Ventilation and Air Conditioning 🢒 Air Delivery Improper

Step

Action

Yes

No

1

Did you perform the function test?

Go to Step  2

Go to Function Test

2
  1. Set the blower speed to HIGH.
  2. Set the mode control to the VENT position.
  3. Set the temperature control to the coldest position.
  4. Inspect for airflow at the following outlets:
    5. • The vent
    • The heater
    • The defroster
    • The side window defroster outlets

Is there airflow through the vent outlets at ambient temperature and no airflow through the heater, defroster and side window defroster outlets?

Go to Step  3

Go to Step  5

3
  1. Set the mode control to the HEAT position.
  2. Set the temperature control to the hottest position.
  3. Inspect for airflow at the following outlets:
    4. • The vent
    • The heater
    • The defroster
    • The side window defroster outlets

Is there hot airflow through the heater outlet at the blower hi speed, minimum hot airflow through the defroster and side window defroster outlets, and no airflow through the vent outlets?

Go to Step 4

Go to Step  5

4
  1. Set the mode control to the DEFROST position.
  2. Inspect for airflow at the following outlets:
    3. • The vent
    • The heater
    • The defroster
    • The side window defroster outlets

Is there hot airflow through the defroster outlet at the blower hi speed, minimum hot airflow through the heater and side window defroster outlets, and no airflow through the vent outlets?

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Go to Step  5

5
  1. Disconnect the affected control cables at the doors.
  2. Inspect the door travel and effort.

Is the door travel and effort OK?

Go to Step 6

Go to Step 8

6

Test the control cable travel by moving the corresponding control at the heater control unit.

Is the control cable travel OK?

Go to Step 7

Go to Step 9

7
  1. Inspect the control cables attachment at the heater control unit
  2. Repair as necessary. Refer to Control Assembly Replacement .

Is the repair complete?

Go to Function Test

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8

Repair the affected door at the heater case as necessary. Refer to HVAC Module Assembly Replacement .

Is the repair complete?

Go to Function Test

--

9

Repair or replace the affected control cables as necessary. Refer to the following:

Is the repair complete?

Go to Function Test

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